This tutorial will show you how to delete
Deleting a subdomain does not delete the subdomain folder - you will
need to do this manually.
To delete a subdomain:
Click on the Subdomains link in the Domain Control area.
Select the required subdomain from the "Delete subdomain" drop-down
Click on the Delete button. Click on the Subdomains link to
return to the Subdomain window to confirm that it has been deleted.